It is odd that service in so many LDS's is iffy. I have had mainly lousy experiences. I have been sold stuff that doesn't fit or that isn't ideal or the best, simply because they wanted to sell me what they had in stock. Moreover, I have been made to feel that they don't like hassles--returns or complaints or quips--especially if there is another customer in the store. To my mind, a LDS is only as good as its inventory of items--if it has a very impressive inventory of items--in quality and quantity--then chances are that it has some good and knowledgeable people working there, and chances are better that they'll service you better (though no guarantees). Here in HK, there are some pretty good dive shops with impressive inventories and very decent prices--nearly the complete catalogue of Scubapro, Halcyon, and OMS in one store!--I have never seen anything as good in the US.
In the US, I have always received exactly what I ordered from LP. They haven't always been super friendly--sometimes even a bit rough around the edges--but they don't mess around and they get you what you want and they handle problems quickly and efficiently. And of course they offer great prices. The ideal is to know what you want and to have tried different things in order to learn what floats your boat. Dive shops also have a bit of incentive to keep you relatively ignorant and dependent on them (especially if their inventory is sparse), though some offer classes to teach you how a reg works, etc. If you learn too much, then maybe you want to try a Zeagle but they only carry Seaquest--and then they are not happy with you. Moreover, I personally enjoy diving older models of most gear, particularly older Scubapro regs and computers, and I piece together BP/W setups, and I use old-fashioned spearguns--and I can get most of what I need on Ebay at great prices. The LDS wants to sell me only the newest titanium MK25/X650 (or whatever the newest numbers are), and they are not much interested in my interest in older model equipment. And often they have young staff who never heard of the equipment I want to ask about or have serviced (in the US, I mail my regs to someone who knows; here in HK, I found a great technician who knows all the old stuff inside and out). If you read Scubaboard regularly, poke around elsewhere on the Web, and make an effort to learn about and occasionally try stuff that pops up on Ebay, then you know more than most staff in most LDS. If it were not for LP and Ebay, I would not know anything about this piece of equipment versus that and I likely would not be diving right now. Most LDS's (in many parts of the US, that is, and also elsewhere), have become equal parts travel agents and dive shops. They cater to the exotic tropical trip and sell stuff that might be fine for the occasional vacation to the tropical reef destinations. There are some exceptions that are excellent, but they are few, in my experience. The LDS, generally speaking, is not for the hobbiest (again, there are som exceptions). Ebay and LP and Scubatoys make all sorts of interesting things possible for me that otherwise would not be possible. Just my two cents.